The prior art shows many prefabricated buildings of polygonal shape which can be bolted together at the building site. However, many of these buildings are of very marginal construction and are not only substantially without heat insulation, but are also not well-engineered from the point of view of resisting high winds and other forces tending to warp or destroy them.
U.S. Pat. No. 4,173,855 issued to Raptoplous shows a building which is basically similar to the present invention in that it employs columns in the polygonal corners, the columns supporting roof beams which are joined at their centers and are self-supporting thereat. Other buildings of this general type are shown in U.S. Pat. No. 3,152,366 issued to McCrory et al. and 3,281,999 issued to Keely, in French Pat. No. 1,308,023 (1962), and in German Pat. No. 25,09,078 (1976).
There are a number of patents showing buildings made on a hexagonal grid in which portions of the buildings are shared in common, i.e. U.S. Pat. Nos. 3,372,518 issued to Rensch; 3,527,002 issued to Mead and 3,807,101 issued to Cole.
U.S. Pat. No. 4,068,437 issued to Byxbe et al. shows a building using prefabricated panels which are attached together and coupled to beams made up of two C-shaped members, and German Pat. No. 25,11,271 (1978) shows upright metal columns which support sheet metal beams using tongues which extend into the beams and are apparently spot-welded to them, the tongues being supported on vertical circular columns.